title: cspB encodes a major cold shock protein in Clostridium botulinum ATCC 3502.
abstract: The relative expression of three cold shock protein coding genes (cspA, cspB and cspC) of Clostridium botulinum ATCC 3502 was studied with quantitative RT-PCR analysis following a cold shock shift from 37 °C to 15 °C. A significant increase in the relative expression of all three genes was observed upon the temperature downshift. To validate these findings, single-gene insertional inactivation of cspA, cspB and cspC was undertaken with the ClosTron gene knock-out system. In growth experiments, mutations in cspB or cspC, but not cspA, resulted in a cold-sensitive phenotype. No growth of the cspB mutant was observed at 15°C over a ten day period, whereas at 20 °C the growth rate was 70% lower than that of wild type strain. The growth rate of cspC mutant was 70% and 80% lower than the growth rate of the wild type strain at 15 °C and 20 °C, respectively. At 37 °C the growth of cspB mutant did not differ from, but the growth rate of cspC mutant was 30% lower than, that of the wild type strain. The cspA mutant grew somewhat faster than the wild type strain at all studied temperatures. Since the inactivation of cspB resulted in the most prominent defect in growth at low temperatures, we suggest that cspB encodes the major cold shock protein of C. botulinum ATCC 3502. Understanding the mechanisms behind cold tolerance of C. botulinum helps to evaluate the safety risks this foodborne pathogen poses in the modern food industry.
authors.affiliation: Department of Food Hygiene and Environmental Health, Faculty of Veterinary Medicine, University of Helsinki, Helsinki, Finland. henna.soderholm@helsinki.fi
authors.forename: H
authors.initials: H
authors.lastname: Söderholm
authors.forename: M
authors.initials: M
authors.lastname: Lindström
authors.forename: P
authors.initials: P
authors.lastname: Somervuo
authors.forename: J
authors.initials: J
authors.lastname: Heap
authors.forename: N
authors.initials: N
authors.lastname: Minton
authors.forename: J
authors.initials: J
authors.lastname: Lindén
authors.forename: H
authors.initials: H
authors.lastname: Korkeala
mesh_terms: D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism*; D001483:Base Sequence; D003014:Clostridium botulinum / Q000235:genetics* / Q000254:growth & development* / Q000378:metabolism; D057773:Cold Shock Proteins and Peptides / Q000235:genetics / Q000378:metabolism*; D003080:Cold Temperature; D004269:DNA, Bacterial / Q000235:genetics; D015964:Gene Expression Regulation, Bacterial; D055786:Gene Knockout Techniques; D008969:Molecular Sequence Data; D009154:Mutation; D017422:Sequence Analysis, DNA
chemical_list: D001426:Bacterial Proteins; D057773:Cold Shock Proteins and Peptides; D004269:DNA, Bacterial; C077188:cold-shock protein CspB, Bacteria